TypeScript 5.9 introduces several developer experience improvements including a streamlined tsc --init that generates minimal configuration files with modern defaults, support for ECMAScript's import defer syntax for deferred module evaluation, and a stable --module node20 option. The release also enhances editor tooling with expandable hover tooltips, configurable hover length, and improved DOM API documentation with summary descriptions. Performance optimizations include better type instantiation caching and reduced closure creation in file system operations.
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What’s New Since the Beta and RC? Copy linkMinimal and Updated tsc --init Copy linkSupport for import defer Copy linkSupport for --module node20 Copy linkSummary Descriptions in DOM APIs Copy linkExpandable Hovers (Preview) Copy linkConfigurable Maximum Hover Length Copy linkOptimizations Copy linkNotable Behavioral Changes Copy linkType Argument Inference Changes Copy linkWhat’s Next? Copy link1 Comment
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